1. Field of the Invention
The present invention relates to display devices having a function of adjusting a height position and a tilt angle of a monitor.
2. Description of the Related Art
Display devices for vehicles are commonly used which include a raising and lowering mechanism for moving a monitor to a use position and a tilt mechanism for adjusting a tilt angle of a monitor, and the raising and lowering mechanism and the tilt mechanism are operated by a motor as a drive source. As a conventional example of such display devices, Japanese Unexamined Patent Application Publication No. 2010-12880 discloses a display device which includes first and second guide holes on a base which is disposed on the back face of a monitor and first and second shafts that engage with the first and second guide holes, respectively, on a bracket which supports the monitor so as to perform a raising and lowering operation and a tilt operation by moving the first and second shafts along the corresponding first and second guide holes when a drive force in the up and down direction is applied from a drive mechanism mounted on the base to the bracket. The first guide hole is formed as an elongated hole which straightly extends in the up and down direction, while the second guide hole has a straight portion which extends parallel to the first guide hole and an inclined portion which extends from the upper end of the straight portion.
In the display device having such a general configuration, the monitor can be moved to a use position by a raising and lowering operation when the first shaft is guided by the first guide hole to move in the up and down direction and the second shaft is guided by the straight portion of the second guide hole to move in the up and down direction. Further, the monitor can be held at a desired tilt angle by a tilt operation since the bracket pivots about the first shaft when the first shaft is guided at a position adjacent to the upper end of the first guide hole and the second shaft is guided by the inclined portion of the second guide hole after passing the straight portion of the second guide hole.
However, in the display device disclosed in Japanese Unexamined Patent Application Publication No. 2010-12880, the raising and lowering operation and the tilt operation of the monitor are switched according to the engagement position of the second shaft which moves along the straight portion and the inclined portion of the second guide hole. As a result, the height position in which the tilt angle of the monitor is adjusted is limited to one location, and this may cause a problem that a tilt adjustment may not be performed at an optimal raised and lowered position desired by a user. Further, in order to perform tilt adjustment of the monitor, it is necessary to provide a third guide hole on the bracket and a third shaft on the base to be guided by the third guide hole, which leads to a complicated structure. In addition, since the positions of the first to third guide holes and the first to third shafts need to be offset in the front and back direction, the entire depth dimension of the display device becomes large, which causes a problem that the display device may not be used in a certain type of vehicle which does not have a sufficient space for installation.